Liquid crystal display and electronic device

ABSTRACT

To provide a liquid crystal display capable of obtaining light and high-contrast display having a wide viewing angle in a transflective liquid crystal display. A liquid crystal display of the present invention employs a vertical alignment mode using a liquid crystal layer  50  that is vertically aligned in the initial alignment state, wherein a transparent display area T is disposed to surround the periphery of a reflective display area R in one dot, and an insulating film  21  is provided in the area that corresponds to the reflective display area R in the center of the dot, the insulating film  21  making the thickness of the liquid crystal layer  50  in the reflective display area R smaller than the thickness of the liquid crystal layer  50  in the transparent display area T.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a liquid crystal display and anelectronic device. More specifically, the invention relates to atechnique of obtaining a high-contrast display having a wide viewingangle in a transflective liquid crystal display that performs display inboth a reflective mode and a transparent mode.

2. Description of Related Art

Since reflective liquid crystal displays have no light sources, such asa backlight, they consume low power, and thus can be used for variousportable electronic devices. However, the reflective liquid crystaldisplays perform display using outside light, such as sunlight andillumination light. Thus, these displays are subject to low visibilityin a dark place. Therefore, the related art includes liquid crystaldisplays capable of making display visible using outside light in alight place, as in general reflective liquid crystal displays, and usingan inside light source, such as a backlight, in a dark place. In otherwords, such liquid crystal displays employ a reflective and transparentdisplay system, thereby allowing clear display even in low light whilereducing power consumption by switching the display system between thereflective mode and the transparent mode depending on the surroundingbrightness. Hereinafter, in this specification, liquid crystal displaysof this type are referred to as “transflective liquid crystal displays.”

Such related art transflective liquid crystal displays include a liquidcrystal display having a structure in which a liquid crystal layer issandwiched between an upper substrate and a lower substrate. Areflective film having a light-transmitting window in a metallic filmmade of aluminum or the like is provided on the inner surface of thelower substrate, and this reflective film functions as a transflectivefilm. In this case, in a reflective mode, outside light that has enteredfrom the upper substrate passes through the liquid crystal layer, isthen reflected by the reflective film, again passes through the liquidcrystal layer, and outgoes from the upper substrate, thus contributingto display. On the other hand, in a transparent mode, light from thebacklight, which has entered from the lower substrate, passes throughthe liquid crystal layer from the window of the reflective film, andthen emerges from the upper substrate to the exterior, therebycontributing to display. Accordingly, in the reflective-film formedarea, the area which has the window serves as a transparent display areaand the other area serves as a reflective display area.

Liquid crystal alignment modes include a twisted nematic (hereinafter“TN”) mode in which liquid crystal molecules exhibit a twisted alignmentsubstantially parallel to the substrate surface and vertical to thesubstrate; and a vertical alignment mode in which liquid crystalmolecules exhibit vertical alignment, under a no voltage applied state.Although, in the related art, the TN mode can be viewed as reliable, therelated art also includes liquid crystal displays that in the verticalalignment mode can provide some excellent characteristics.

For example, in the vertical alignment mode, since the state in whichthe liquid crystal molecules are aligned vertically to the substratesurface (there is no optical retardation as viewed from the normal) isused as black display, the black display is superior in quality, thusproviding high contrast. In vertical-alignment LCDs which are superiorin front contrast, the range of viewing angle in which a fixed contrastcan be obtained is wider than that of the horizontal-alignment-mode TNliquid crystal. Furthermore, employing an alignment dividing(multidomain) technique of dividing the alignment orientation of aliquid crystal in pixels provides a remarkably wide viewing angle.

In the transflective liquid crystal display with the aforesaidstructure, the retardation of the liquid crystal in the reflectivedisplay area is expressed by: 2×Δn·d, because the incident light passesthrough the liquid crystal layer two times and then reaches theobserver, where the thickness of the liquid crystal layer is d, therefractive index anisotropy of the liquid crystal is: Δn, and theretardation of the liquid crystal which is expressed as their integratedvalue is: Δn·d. On the other hand, the retardation of the liquid crystalin the transparent display area is expressed by: 1×Δn·d, because thelight from the backlight passes through the liquid crystal layer onlyonce.

As described above, when the alignment of the liquid crystal moleculesof the liquid crystal layer is controlled, even with the structurehaving different retardation values in the reflective display area andin the transparent display area, an electric field has been applied tothe liquid crystal at the same driving voltage in both display modes. Insuch a case, when the liquid crystal with different display modes, inother words, the liquid crystal with different retardations between thetransparent display area and the reflective display area is aligned atthe same driving voltage, it poses a problem of obtaining nohigh-contrast display. In order to address or solve the problem, aliquid crystal display is disclosed in Japanese Unexamined PatentApplication Publication No. 11-242226 that has a structure havingdifferent thicknesses of the liquid crystal layer in the transparentdisplay area and in the reflective display area.

SUMMARY OF THE INVENTION

As described above, using the vertical alignment mode can also be usedto achieve high contrast. Therefore, a liquid crystal display with acombination of the transflective liquid crystal display and the verticalalignment mode can be beneficial. However, problems exist with such astructure, including a problem of decreased contrast due to thedifference in retardation in the reflective and transparent displaymodes, problems of alignment control and alignment division in thevertical alignment mode, and so on, thus preventing such a display frombecoming realized.

The present invention addresses or solves the above and/or otherproblems, and provides a liquid crystal display capable of obtaininglight and high-contrast display having a wide viewing angle in atransflective liquid crystal display.

In order to address or achieve the above, a liquid crystal displayaccording to the present invention includes a liquid crystal layersandwiched between a pair of substrates, and separately having atransparent display area for transparent display and a reflectivedisplay area for reflective display in one dot area. The liquid crystallayer exhibits vertical alignment in the initial alignment state. Aninsulating film is provided between at least one of the pair ofsubstrates and the liquid crystal layer and in at least the reflectivedisplay area, the insulating film making the thickness of the liquidcrystal layer in the reflective display area and in the transparentdisplay area different owing to its film thickness.

The liquid crystal display of the present invention is a combination ofa transflective liquid crystal display and a liquid crystal in avertical alignment mode. A transflective liquid crystal display can beprovided with a structure in which, in order to address or solve theproblem of reduction in contrast due to the difference of retardationbetween the reflective and the transparent display modes, the thicknessof the liquid crystal layer is varied in the reflective display area andin the transparent display area by forming an insulating film with afixed thickness in the reflective display area on the lower substrate soas to project toward the liquid crystal layer. The applicants havestudied this type of liquid crystal display. With such a structure, thethickness of the liquid crystal layer in the reflective display area canbe made to be smaller than that of the liquid crystal layer in thetransparent display area owing to the presence of the insulating film.Therefore, the retardation in the reflective display area and theretardation in the transparent display area can be sufficiently close toor substantially equal to each other, thereby allowing an increase incontrast.

The inventors have found that the alignment orientation of the liquidcrystal in a vertical alignment mode during the application of anelectric field can be controlled by combining a liquid crystal layer ina vertical alignment mode to the liquid crystal display having the aboveinsulating film. More specifically, a negative liquid crystal isgenerally used when the vertical alignment mode is employed. However,the direction in which the liquid crystal molecules fall cannot becontrolled without any considerations (unless a pre-tilt is given)because the liquid crystal molecules are brought down from a state ofstanding vertically to the substrate surface in the initial alignmentstate, thus generating disturbance of alignment (disclination) to causeimperfect display such as light dropout, resulting in a decrease indisplay quality. Therefore, when the vertical alignment mode isemployed, an important factor is to control the alignment orientation ofthe liquid crystal molecules in applying an electric field. In theliquid crystal display having the aforesaid insulating film, theinsulating film projects toward the liquid crystal layer, which servesas a projection. Thus, a pre-tilt that corresponds to the shape of theprojection can be given with the liquid crystal molecules verticallyaligned in the initial state. Due to this action, the alignmentorientation when an electric field is applied to the liquid crystalmolecules can be controlled. Consequently, high-contrast display can beachieved without imperfect display, such as light drop.

With the structure of the present invention, the transflective liquidcrystal display in a vertical alignment mode has an insulating film.Accordingly, the problem of reduction in contrast due to the differenceof retardation between the reflective and the transparent display modescan be addressed or solved, which is a fundamental problem of thetransflective liquid crystal display, and imperfect display, because ofthe fact that the alignment orientation of the liquid crystal moleculesin the vertical alignment mode cannot be controlled, can be reduced.Consequently, both the advantage of the vertical alignment mode and theadvantage of the transflective type can fully be taken to realize aliquid crystal display of high display quality.

The arrangement of the transparent display area and the reflectivedisplay area in one dot area can be set arbitrarily. However, it ispreferable to arrange the transparent display area so as to surround theperiphery of the reflective display area and to arrange the insulatingfilm in the area that corresponds to the reflective display area in thecenter of the dot.

From such a viewpoint, another liquid crystal display of the presentinvention includes a liquid crystal layer sandwiched between a pair ofsubstrates, and separately having a transparent display area fortransparent display and a reflective display area for reflective displayin one dot area. An insulating film is provided between at least one ofthe pair of substrates and the liquid crystal layer and in at least thereflective display area, the insulating film making the thickness of theliquid crystal layer in the reflective display area and in thetransparent display area different owing to its film thickness. Thethickness of the liquid crystal layer in the center of the dot area isset to be smaller than in the periphery in the one dot area.

With such a structure, if a rectangular reflective display area isprovided in the center of one dot area and a rectangular insulating filmis disposed therein, around which a transparent display area is formed,the alignment orientations of the liquid crystal molecules are specifiedto four orientations that are perpendicular to each side of therectangle with the insulating film in the center of the dot as thecenter. As a result, four areas that each have a different alignmentorientation are formed in one dot area to realize an alignment dividingstructure, thus achieving a wide viewing angle.

Alternatively, contrarily to the aforesaid structure, it is alsopossible to have a structure in which an insulating film is providedbetween at least one of the pair of substrates and the liquid crystallayer and in at least the reflective display area, the insulating filmmaking the thickness of the liquid crystal layer in the reflectivedisplay area and in the transparent display area different owing to itsfilm thickness. The thickness of the liquid crystal layer in theperiphery of the one dot area is set to be smaller than in the center.More specifically, the reflective display area is provided so as tosurround the periphery of the transparent display area in the one dot.The insulating film is disposed in the area corresponding to thereflective display area in the periphery of the dot.

With such a structure, if a rectangular reflective display area isprovided in the center of one dot area, a rectangular-frame-shapedinsulating film is disposed on the outside thereof, and a reflectivedisplay area is formed in the periphery thereof, the alignmentorientations of the liquid crystal molecules are specified to fourorientations that are perpendicular to each side of the rectangularframe from the insulating film in the periphery of the dot area towardthe center. As a result, four areas that each have a different alignmentorientation are formed in one dot area, as in the aforesaid structure,to realize an alignment dividing structure, thus achieving a wideviewing angle.

Preferably, the insulating film includes an inclined area in thevicinity of the boundary between the reflective display area and thetransparent display area, the inclined area having an inclined plane sothat its thickness continuously varies.

The end of the insulating film, which corresponds to the boundarybetween the reflective display area and the transparent display area,may have a step-like difference in thickness. However, in such a case,the thickness of the liquid crystal layer sharply changes because of theaforesaid step in the vicinity of the boundary between the reflectivedisplay area and the transparent display area, thus causing alignmentdisturbance of the liquid crystal to exert a bad influence upon display.On the other hand, when the insulating film has an inclined plane so asto continuously vary the thickness thereof, the alignment of the liquidcrystal also varies continuously depending on the position of theinclined plane of the insulating film, thus causing no large orsubstantial disturbance of alignment to prevent or reduce imperfectdisplay. When the insulating film is rectangular, as described above,the inclined plane is also inclined in four directions perpendicularlycrossing each other. Therefore, the presence of the inclined planeallows smooth formation of the alignment dividing structure.

It is also possible to provide an electrode to drive the liquid crystallayer to the substrate having the insulating film and to provide a noelectrode formed area where the electrode is absent in at least part ofthe inclined plane of the insulating film.

With the structure of the present invention, as described above, merelyproviding an insulating film that is a projection projecting toward theliquid crystal layer allows control of alignment orientation. However,when no electrode formed area is provided to at least part of theinclined plane of the insulating film, an electric field (potentiallines) generating between the electrodes on both the substrates isdistorted in the vicinity of the no electrode formed area. The action ofthe distorted electric field allows smooth or substantially smoothcontrol of the alignment orientation of the liquid crystal molecules.

Assuming that the center of one dot is a rectangular reflective displayarea, the periphery is a transparent display area and arectangular-frame-shaped no electrode formed area is provided in theinclined area of the insulating film, which corresponds to the boundarybetween the reflective display area and the transparent display area,the electrode of the reflective display area and the electrode of thetransparent display area are completely separated. Therefore, it becomesdifficult to apply the same driving voltage to both of them at the sametime. Accordingly, it is preferable to provide a structure in which theelectrode in the reflective display area and the electrode in thetransparent display area, which are provided on both sides of the noelectrode formed area, are electrically connected through a connectingsection formed of the same layer as the electrodes. Alternatively, it isalso preferable to provide a structure in which the electrode in thereflective display area and the electrode in the transparent displayarea are electrically connected through a connecting section formed of adifferent layer from the electrodes. With such a structure, the samedriving voltage can easily be applied simultaneously to the electrode inthe reflective display area and the electrode in the transparent displayarea.

When one of the substrates is an element substrate having a pixelelectrode and a switching element and the other substrate is an opposedsubstrate having a common electrode and the insulating film, it ispreferable to dispose a contact hole to electrically connect the pixelelectrode and the switching element on the one substrate in the positionnot overlapping the inclined area.

Since the contact hole that electrically connects the pixel electrodeand the switching element is formed on the upper layer of one substrate,the pixel electrode is generally recessed at the portion of the contacthole. Therefore, with the aforesaid structure, the electric field thathas been distorted in the vicinity of the no electrode formed area isfurther distorted because of the recess of the pixel electrode, therebyfacilitating control of the alignment of the liquid crystal molecules.

Furthermore, when an electrode to drive the liquid crystal layer and aninsulating film are provided on one of the pair of substrates, and anelectrode to drive the liquid crystal layer is provided on the othersubstrate, it is preferable that the electrode on the other substrateinclude a window on the outside of the inclined area of the insulatingfilm.

With the structure of the present invention, as described above, merelyproviding the insulating film that is a projection projecting toward theliquid crystal layer allows control of alignment orientation. However,when the electrode on the other substrate, which is opposed to theinsulating film, has a window on the outside of the inclined area of theinsulating film, an electric field generating between the electrodes onboth the substrates tilts because there are no electrodes at the window.The action of the tilted electric field allows smoother control of thealignment orientation of the liquid crystal molecules.

When the insulating film has an inclined plane, it is preferable thatthe inclination angle of the inclined plane of the insulating filmrelative to the substrate surface be in the range of 5° to 50°. Theinclined plane may be either planar or curved. Here, “the inclinationangle of the inclined plane” means an angle θ formed by the tangentialline S of an inclined plane in the position where the layer thickness inthe inclined area is h/2, and a substrate surface (planar plane), wherethe thickness of the flat part of the insulating film is h.

When the inclination angle is less than 5°, it forms a gentle inclinedplane. Therefore, the inclined area increases in size to have too largean area where the retardation becomes fragmentary, thus increasingoptical loss. On the other hand, when the inclination angle exceeds 50°,it forms a steeply inclined plane. Therefore, the liquid crystalmolecules are aligned vertically to the inclined plane when non-selectedvoltage is applied, thereby generating disclination between the liquidcrystal molecules on the inclined plane and those on the planar plane.Consequently, black floating (a leak of light) occurs to decrease incontrast. Therefore, it is desirable that the inclination angle be inthe range of 5° to 50°.

The outline of the insulating film in one dot area is not particularlylimited, and the invention can include various shapes. However, when itis an equilateral polygon or a circle, the liquid crystal molecules areuniformly divided in each direction in one dot area. As a result, aviewing angle at which high contrast is obtained can be isotropicallywidened.

Furthermore, providing a circularly-polarized-light radiating device toradiate circularly polarized light to the one substrate or the othersubstrate allows preferable reflective display and transparent display.

An electronic device of the present invention includes the liquidcrystal display according to the present invention.

With such a structure, electronic devices can be provided which have alight and high-contrast liquid crystal display having a wide viewingangle irrespective of use environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic circuit diagram of a plurality of dots arranged inthe form of matrix which constitute an image display area of a liquidcrystal display according to a first exemplary embodiment of the presentinvention;

FIG. 2 is a plan view showing the structure of an adjacent plurality ofdots on a TFT array substrate which constitutes the liquid crystaldisplay of the same;

FIG. 3 is a sectional view taken along plane A-A′ of FIG. 2, showing thestructure of the liquid crystal display of the same;

FIG. 4 is a plan view showing the structure of an adjacent plurality ofdots on a TFT array substrate, which constitutes a liquid crystaldisplay according to a second exemplary embodiment of the presentinvention;

FIG. 5 is a sectional view taken along plane A-A′ of FIG. 4, showing thestructure of the liquid crystal display of the same;

FIG. 6 is a sectional view showing the structure of a liquid crystaldisplay according to a third exemplary embodiment of the presentinvention;

FIG. 7 is a plan view showing the structure of an adjacent plurality ofdots on a TFT array substrate, which constitutes a liquid crystaldisplay according to a fourth exemplary embodiment of the presentinvention;

FIG. 8 is a sectional view taken along plane A-A′ of FIG. 7, showing thestructure of the liquid crystal display of the same;

FIG. 9 is a plan view showing the structure of an adjacent plurality ofdots on a TFT array substrate, which constitutes a liquid crystaldisplay according to a fifth exemplary embodiment of the presentinvention;

FIG. 10 is a sectional view taken along plane A-A′ of FIG. 9, showingthe structure of the liquid crystal display of the same;

FIG. 11 is a sectional view showing the structure of a liquid crystaldisplay according to a sixth exemplary embodiment of the presentinvention;

FIG. 12 is a sectional view showing the structure of a liquid crystaldisplay according to a seventh exemplary embodiment of the presentinvention;

FIG. 13 is a graph explaining the inclination angle of an insulatingfilm of the present invention;

FIG. 14 is a perspective view showing an example of an electronic deviceof the present invention;

FIG. 15 is a perspective view showing another example of an electronicdevice of the present invention; and

FIG. 16 is a perspective view showing still another example of anelectronic device of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1 to 3, a first exemplary embodiment of the presentinvention is described below.

A liquid crystal display of this exemplary embodiment is an example ofan active-matrix liquid crystal display that uses a thin film transistor(hereinafter “TFT”) as a switching element.

FIG. 1 is a schematic circuit diagram of a plurality of dots arranged inthe form of matrix which constitute an image display area of the liquidcrystal display according to this exemplary embodiment. FIG. 2 is a planview showing the structure of the adjacent plurality of dots on a TFTarray substrate. FIG. 3 is a sectional view taken along plane A-A′ ofFIG. 2, showing the structure of the liquid crystal display. In thefollowing drawings, the layers and members are scaled variously in orderto make them discernible on the drawings, and are not representative oftheir actual sizes.

In the liquid crystal display of this exemplary embodiment, each of theplurality of dots constituting an image display area and arranged in theform of matrix includes a pixel electrode 9 and a TFT 30 serving as aswitching element to control the pixel electrode 9, and a data line 6 a,to which an image signal is supplied, is electrically connected to thesource of the TFT 30 as shown in FIG. 1. Image signals S1, S2, . . . ,Sn, which are written to the data line 6 a, are line-sequentiallysupplied in this order or, alternatively, supplied to the adjacentplurality of data lines 6 a by group. A scanning line 3 a iselectrically connected to the gate of the TFT 30, and scanning signalsG1, G2, . . . , Gm are line-sequentially applied to the plurality ofscanning lines 3 a at a fixed timing and in pulse. The pixel electrode 9is electrically connected to the drain of each TFT 30, and write theimage signals S1, S2, . . . , Sn supplied over the data lines 6 a at afixed timing by turning on the TFT 30 serving as a switching element foronly a fixed period of time.

The image signals S1, S2, . . . , Sn, which were written to the liquidcrystal through the pixel electrodes 9, are held between the pixelelectrodes 9 and a common electrode, which are described below, for afixed period of time. The liquid crystal modulates light by varying theorientation and order of the molecular association depending on theapplied voltage level, thereby allowing gray scale to be assigned. Astorage capacitor 70 is added in parallel with a liquid crystalcapacitor formed between each pixel electrode 9 and the common electrodein order to prevent or reduce leakage of the held image signals.Reference numeral 3 b denotes a capacitor line.

Next, referring to FIG. 2, the planar structure of the TFT arraysubstrate that constitutes the liquid crystal device of this exemplaryembodiment is described below.

As shown in FIG. 2, the plurality of rectangular pixel electrodes 9 (theoutline is shown by the dotted line 9A) is arranged in the form ofmatrix on the TFT array substrate, and the data lines 6 a, the scanninglines 3 a, and the capacitor lines 3 b are provided along the verticaland horizontal boundaries of the pixel electrodes 9. In this exemplaryembodiment, the inside of the area having each pixel electrode 9 and thedata line 6 a, the scanning line 3 a, and the capacitor line 3 bdisposed to surround each pixel electrode 9 forms one dot area, having astructure capable of displaying for each dot area disposed in matrixform.

The data line 6 a is electrically connected to a later-described sourcearea of a semiconductor layer 1 a constituting the TFT 30 and formed of,for example, a polysilicon film, through a contact hole 5. Each pixelelectrode 9 is electrically connected to a later-described drain area ofthe semiconductor layer 1 a through a contact hole 8. The scanning line3 a is arranged so as to face a channel area (left-upward obliquelyshaded area in the drawing) of the semiconductor layer 1 a, the scanningline 3 a functioning as a gate electrode at a portion facing the channelarea.

The capacitor line 3 b includes a main line section (a first area alongthe scanning line 3 a in plan view) extending substantially linearlyalong the scanning line 3 a, and a projecting section (a second areaextending along the data line 6 a in plan view) projecting from aportion intersecting the data line 6 a toward the preceding stage(upward in the drawing) along the data line 6 a. In FIG. 2, the areashown by a right-upward obliquely shaded area includes a plurality offirst light shielding films 11 a.

More specifically, the first light shielding films 11 a are eacharranged in the position to cover the TFTs 30 including the channel areaof the semiconductor layer 1 a, as viewed from the TFT array substrateside, and include a main line section extending linearly along thescanning line 3 a and facing the main line section of the capacitor line3 b, and a projecting section projecting from a portion intersecting thedata line 6 a toward the adjacent post stage (downward in FIG. 2) alongthe data line 6 a. The end of the downward projecting section in eachstage (pixel row) of the first light shielding films 11 a overlaps theend of the upward projecting section of the post-stage capacitor line 13b under the data line 6 a. The overlapped portions each include acontact hole 13 that electrically connects the first light shieldingfilm 11 a and the capacitor line 3 b to each other. In other words, inthis exemplary embodiment, the first light shielding films 11 a areelectrically connected to the preceding- or post-stage capacitor line 3b through the contact holes 13.

As shown in FIG. 2, a rectangular reflective film 20 is formed in thecenter of one dot area, an area including the reflective film 20 servingas a reflective display area R and the peripheral area including noreflective film 20 serving as a transparent display area T. Also, arectangular insulating film 21 is formed so as to include the areaincluding the reflective film 20 therein in plan view.

Referring to FIG. 3, the sectional structure of the liquid crystaldisplay of this exemplary embodiment is described below. FIG. 3 is asectional view taken along plane A-A′ of FIG. 2. However, the presentinvention provides in the structure of the insulating film in the centerof the dot and the sectional structures of the TFT and other wirings arethe same as those of the related art structure, so that the drawing andthe description of the TFT and wirings are omitted.

As shown in FIG. 3, a liquid crystal layer 50 formed of a liquid crystalthat is vertically aligned in the initial alignment state is sandwichedbetween a TFT array substrate 10 and an opposed substrate 25 opposedthereto. The TFT array substrate 10 includes the reflective film 20formed of a high-reflective metallic film, such as aluminum and silver,on the surface of a substrate main body 10A made of a translucentmaterial such as quartz and glass. As described above, the areaincluding the reflective film 20 serves as the reflective display area Rand the area including no reflective film 20 serves as the transparentdisplay area T.

A dye layer 22R constituting a color filter for reflective display isformed on the reflective film 20 located in the reflective display areaR. A dye layer 22T constituting a color filter for transparent displayis formed on the substrate located in the transparent display area T.Generally, in the transflective liquid crystal display, light passesthrough a color filter two times in the reflective display, while in thetransparent display, it passes only once, thus posing a problem ofdifferent display chroma between the reflective display and thetransparent display. Accordingly, the applicant has proposed a techniqueof enhancing the balance of display color between the reflective displayand the transparent display by changing the color purity of the dyelayer of the color filter between in the reflective display area and inthe transparent display area. The aforesaid dye layers of thereflective-display color filter and the transparent-display color filteremploy the technique.

The respective dye layers 22R and 22T of the reflective-display colorfilter and the transparent-display color filter have an insulating film21 in the position corresponding to the reflective display area R. Theinsulating film 21 is made of an organic film, such as an acrylic resin,having a film thickness of about 2 to 3 μm, having an inclined area Kincluding an inclined plane 21 a so as to vary the thickness of theinsulating film 21 continuously in the vicinity of the boundary betweenthe reflective display area R and the transparent display area T. Sincethe thickness of a liquid crystal layer 50 at the portion including noinsulating film 21 is about 4 to 6 μm, the thickness of the liquidcrystal layer 50 in the reflective display area R is about one-half ofthe thickness of the liquid crystal layer 50 in the transparent displayarea T. In other words, the insulating film 21 works as aliquid-crystal-layer-thickness control layer to make the thickness ofthe liquid crystal layer 50 different between in the reflective displayarea R and the transparent display area T owing to its film thickness.The angle θ formed by the surface of the dye layers 22R and 22T of thecolor filters and the inclined plane 21 a of the insulating film 21 isabout 5° to 50°. In this exemplary embodiment, the edge of the planarplane at the upper part of the insulating film 21 and the edge of thereflective film 20 (reflective display area) coincide substantially witheach other, the inclined area K being included in the transparentdisplay area T.

The surface of the TFT array substrate 10 that includes the surface ofthe insulating film 21 has the pixel electrodes 9 made of a transparentconductive film, such as indium tin oxide (hereinafter, abbreviated toITO) and an alignment film 23 made of polyimide or the like.

On the other hand, the opposed substrate 25 has a common electrode 31made of a transparent conductive film, such as an ITO, and an alignmentfilm 33 made of polyimide or the like on a substrate main body 25A madeof a translucent material, such as glass and quartz. The respectivealignment films 23 and 33 of the TFT array substrate 10 and the opposedsubstrate 25 are both subjected to vertical alignment treatment.

The TFT array substrate 10 has a circularly polarizing plate on theouter surface thereof, and the opposed substrate 25 also has acircularly polarizing plate on the outer surface, which are not shown.

According to the liquid crystal display of this exemplary embodiment,since the reflective display area R includes the insulating film 21, thethickness of the liquid crystal layer 50 in the reflective display areaR can be as small as about one-half of the thickness of the liquidcrystal layer 50 in the transparent display area T. Therefore, theretardation in the reflective display area R and the retardation in thetransparent display area T can be made to be substantially equal,thereby enhancing the contrast. Furthermore, since the insulating film21 projects toward the liquid crystal layer 50, which serves as aprojection, a pre-tilt that corresponds to the shape of the projectioncan be given with the liquid crystal molecules 50B vertically aligned inthe initial state. Due to this action, when an electric field is appliedto the liquid crystal molecules 50B, the alignment orientation of theliquid crystal molecules 50B can be controlled. Consequently,high-contrast display can be achieved without imperfect display, such aslight drop.

That is, with the structure of this exemplary embodiment, thetransflective liquid crystal display in a vertical alignment mode hasthe insulating film 21. Accordingly, the problem of reduction incontrast due to the difference of retardation between the reflective andthe transparent display modes can be reduced or solved, and imperfectdisplay because of the fact that the alignment orientation of the liquidcrystal molecules in the vertical alignment mode cannot be controlledcan be reduced. Consequently, both the advantage of the verticalalignment mode and the advantage of the transflective type can be fullytaken to realize a liquid crystal display of high display quality.

In this exemplary embodiment, the rectangular reflective display area Ris provided in the center of one dot area and the rectangular insulatingfilm 21 is disposed at a portion corresponding to the reflective displayarea R in the center of the dot area. Therefore, the alignmentorientations of the liquid crystal molecules are specified to fourorientations that are perpendicular to each side of the rectangle withthe insulating film 21 in the center of the dot as the center. As aresult, four areas (domains) each having a different alignmentorientation are formed in one dot area to realize an alignment dividingstructure, thus achieving a wide viewing angle.

The insulating film 21 includes the inclined area K in the vicinity ofthe boundary between the reflective display area R and the transparentdisplay area T, and the alignment of the liquid crystal molecules 50Bvaries continuously depending on the position of the inclined plane 21 aof the insulating film 21. Accordingly, no large alignment turbulenceoccurs, thus preventing or reducing imperfect display. The inclinedplane 21 a of the insulating film 21 is also inclined in four directionsperpendicularly intersecting each other. Thus, the presence of theinclined plane 21 a allows smooth formation of the alignment dividingstructure.

Referring to FIGS. 4 and 5, a second exemplary embodiment of the presentinvention is described below.

The principle structure of a liquid crystal display of this exemplaryembodiment is similar to that of the first exemplary embodiment, but isonly different in that the common electrode has a window for alignmentcontrol. Therefore, in FIGS. 4 and 5, components that are common tothose of FIGS. 2 and 3 are given the same reference numerals and adetailed description thereof is omitted.

In this exemplary embodiment, as shown in FIGS. 4 and 5, the structureof the TFT array substrate 10 is not different from that of the firstexemplary embodiment. However, a common electrode 31 on the opposedsubstrate 25 has a window 31M. Two windows 31M are provided for one dotthat is formed in a long rectangular shape along the data line 6 a inplan view. The windows 31M are located on the outside of the inclinedarea K of the insulating film 21.

As described in the first exemplary embodiment, with the structure ofthe present invention, merely providing the insulating film that is aprojection toward the liquid crystal layer allows control of alignmentorientation. However, as in this exemplary embodiment, when the windows31M are provided in the common electrode 31 on the opposed substrate 25that faces the insulating film 21 and on the outside of the inclinedarea K of the insulating film 21, an electric field generating betweenthe electrodes on both the substrates tilts because the windows 31Minclude no electrodes. The action of the inclined electric field allowssmoother control of the alignment orientation of the liquid crystalmolecules 50B. The broken lines shown in the liquid crystal layer 50 ofFIG. 5 are potential lines. The liquid crystal molecules 50B are alignedalong the potential lines, thus being aligned smoothly withoutgenerating disclination due to the insulating film 21.

The shape of the window is not limited to that shown in FIG. 4, andinstead may be formed in a rectangular ring shape in accordance with thefour-directional domains. However, in that case, the inside and theoutside of the window must be electrically connected as one electrode;therefore, preferably, it is not a perfectly continuous rectangular ringand instead the inside and the outside of the window are connected at anarbitrary portion.

Referring to FIG. 6, a third exemplary embodiment of the presentinvention is described below.

The principle structure of a liquid crystal display of this exemplaryembodiment is similar to that of the first and second exemplaryembodiments, but is different in the position of the insulating film.Therefore, in FIG. 6, components that are common to FIGS. 3 and 5 aregiven the same reference numerals and a detailed description thereof isomitted.

In the first and second exemplary embodiments, the insulating film 21 isprovided in the center of one dot. On the other hand, in this exemplaryembodiment, the insulating film 21 is disposed near one end of one dot,as shown in FIG. 6. Corresponding to that, only one window 31M isprovided for one dot, that is arranged on the outside of the inclinedarea K of the insulating film 21.

In this exemplary embodiment, since the insulating film 21 is notlocated in the center of the dot, the alignment of the liquid crystalmolecules 50B is not controlled so as to form four domains substantiallyuniformly in one dot, as in the first and second exemplary embodiments.However, it produces the similar advantages to those of the first andsecond exemplary embodiments in that the problem of reduction incontrast due to the difference of retardation between the reflective andthe transparent display modes can be reduced or solved, and imperfectdisplay because of the fact that the alignment orientation of the liquidcrystal molecules in the vertical alignment mode cannot be controlledcan be reduced. Thus, a liquid crystal display of high display qualitycan be realized. Although also this exemplary embodiment has the window31M as in the second exemplary embodiment, the broken lines shown in theliquid crystal layer 50 of FIG. 6 are potential lines, and the liquidcrystal molecules 50B are aligned along the potential lines, thus beingaligned smoothly without generating disclination due to the insulatingfilm 21.

Referring to FIGS. 7 and 8, a fourth exemplary embodiment of the presentinvention is described below.

FIG. 7 is a plan view showing the structure of an adjacent plurality ofdots on a TFT array substrate. FIG. 8 is a sectional view taken alongplane A-A′ of FIG. 7, showing the structure of the liquid crystaldisplay of the same.

The principle structure of a liquid crystal display of this exemplaryembodiment is similar to that of the first to third exemplaryembodiments, but the positional relationship between the reflectivedisplay area R and the transparent display area T is inversed, and theshape of the pixel electrode is different. In FIGS. 7 and 8, componentsthat are common to FIGS. 2 and 3 are given the same reference numeralsand a detailed description thereof is omitted.

The TFT array substrate of this exemplary embodiment has the reflectivefilm 20 shaped like a rectangular frame in the periphery of one dotarea, as shown in FIG. 7. An area including the reflective film 20serves as the reflective display area R, and an area including noreflective film 20, which is inside the reflective display area R,serves as the transparent display area T. In other words, in the firstto third exemplary embodiments, the inside of one dot area is thereflective display area R and the outside is the transparent displayarea T. On the other hand, in this exemplary embodiment, they areinversed. Also, the insulating film 21 shaped like a rectangular frameis formed so as to include the area of the reflective film 20 therein inplan view.

For the sectional structure, the reflective film 20 formed of ahigh-reflective metallic film, such as aluminum and silver; is formed onthe TFT array substrate 10, as shown in FIG. 8. As described above, thearea of the reflective film 20 serves as the reflective display area Rand the area having no reflective film 20 serves as the transparentdisplay area T. The dye layer 22R constituting a reflective-displaycolor filter is provided on the reflective film 20 which is located inthe reflective display area R. The dye layer 22T constituting atransparent-display color filter is provided on the substrate located inthe transparent display area T. On the respective dye layers 22R and 22Tof the reflective-display color filter and the transparent-display colorfilter, the insulating film 21 is formed in the position correspondingto the reflective display area R. The insulating film 21 has theinclined area K including the inclined plane 21 a so as to vary itsthickness continuously in the vicinity of the boundary between thereflective display area R and the transparent display area T. In thisexemplary embodiment, the edge of the planar plane at the upper part ofthe insulating film 21 and the edge of the reflective film 20(reflective display area) coincide substantially with each other, theinclined area K being included in the transparent display area T.

On the surface of the TFT array substrate 10 including the surface ofthe insulating film 21, the pixel electrodes 9 formed of a transparentconductive film, such as an ITO, are provided. However, in the first tothird exemplary embodiments, the pixel electrodes 9 are formed over theentire one dot area. On the other hand, in this exemplary embodiment,the pixel electrodes 9 are formed on the planar plane of the insulatingfilm 21, but are not formed on the inclined plane 21 a, which becomes ano electrode formed area 9N.

This construction is shown as a plan view in FIG. 7, where the areaincluding the pixel electrodes 9 is indicated by a right-downwardobliquely shaded area. More specifically, the insulating film 21includes a recessed area shaped like an inverse quadrangular pyramid inthe center of the dot area, on the inclined plane 21 a of which has nopixel electrodes 9, thus forming the no electrode formed area 9N shapedlike a substantially rectangular frame. However, when the no electrodeformed area 9N is shaped like a rectangular frame, the electrodes on theoutside (reflective display area R) and the electrodes on the inside(transparent display area T) are completely separated. Therefore, thepixel electrodes 9 in the reflective display area R and the pixelelectrodes 9 in the transparent display area T are electricallyconnected through a connecting section 9C formed of an ITO which has thesame layer as the electrodes. With such a structure, the same drivingvoltage can simultaneously be applied to the pixel electrodes 9 in boththe reflective display area R and the transparent display area T. Theconnecting section 9C may be formed of a different layer from the pixelelectrodes 9 and may be connected to the pixel electrodes 9 through acontact hole. Also, as shown in FIG. 8, the alignment film 23 made ofpolyimide or the like is formed on the entire substrate so as to coverthe pixel electrodes 9 and the inclined plane 21 a of the insulatingfilm 21.

On the other hand, the opposed substrate 25 has the common electrode 31made of a transparent conductive film, such as an ITO, and the alignmentfilm 33 made of polyimide or the like on the substrate main body 25Amade of a translucent material, such as glass and quartz. The respectivealignment films 23 and 33 of the TFT array substrate 10 and the opposedsubstrate 25 are both subjected to vertical alignment treatment.

This exemplary embodiment can also produce the similar advantages to thefirst to third exemplary embodiments. More specifically, as described inthe above exemplary embodiments, with the structure of the presentinvention, merely providing the insulating film 21 serving as aprojection that projects toward the liquid crystal layer allows controlof alignment orientation. However, in this exemplary embodiment, thereare no pixel electrodes 9 on the inclined plane 21 a of the insulatingfilm 21. Therefore, an electric field generating between the electrodeson both the substrates is distorted in the vicinity of the inclined areaK. The distortion of the electric field allows much smoother control ofthe alignment orientation of the liquid crystal molecules 50B. Thebroken lines P shown in the liquid crystal layer 50 of FIG. 8 arepotential lines. The liquid crystal molecules 50B are aligned along thepotential lines p, thus being aligned smoothly without generatingdisclination due to the insulating film 21.

Referring to FIGS. 9 and 10, a fifth exemplary embodiment of the presentinvention is described below.

The principle structure of a liquid crystal display of this exemplaryembodiment is similar to that of the fourth exemplary embodiment, but isdifferent in the size of the no electrode formed area. Therefore, inFIGS. 9 and 10, components that are common to FIGS. 7 and 8 are giventhe same reference numerals and a detailed description thereof isomitted.

In the fourth exemplary embodiment, the entire inclined plane 21 a ofthe insulating film 21 is no electrode formed area 9N. On the otherhand, in this exemplary embodiment, only part of the inclined plane 21 aof the insulating film 21 is the no electrode formed area 9N shaped likea slit as shown in FIGS. 9 and 10. In both the fourth and fifthexemplary embodiments, in order to form the no electrode formed area 9N,it is enough to merely make the mask pattern into this shape inpatterning the pixel electrodes 9. Therefore, they are not particularlydifferent in production process from the case without the no electrodeformed area 9N.

Also this exemplary embodiment includes the no electrode formed area 9Nhaving no pixel electrodes 9 on the inclined plane 21 a of theinsulating film 21, thus offering the advantages similar to those of thefourth embodiment, that is, the electric field generating between theelectrodes on both the substrates is distorted in this area, whichallows much smoother control of alignment orientation of the liquidcrystal molecules 50B. The shape, the position and so on of the noelectrode formed area 9N in the fourth and fifth exemplary embodimentsare not particularly limited to the above example, but may be modifiedas appropriate.

Referring to FIG. 11, a sixth exemplary embodiment of the presentinvention is described below.

The principle structure of a liquid crystal display of this exemplaryembodiment is similar to that of the fourth exemplary embodiment, butthe inclination angle of the inclined plane of the insulating film isspecified. Therefore, in FIG. 11, components that are common to FIG. 8are given the same reference numerals and a detailed description thereofis omitted.

When the area of the transparent display area T is relatively large inone dot area (for example, the proportion of the area of the transparentdisplay area T is 50% or more), the reflective film 20 is extendeddownward from the inclined area K of the insulating film 21, and theinclined area K of the insulating film 21 is used as the reflectivedisplay area R, as shown in FIG. 11. The fourth exemplary embodiment(FIG. 8) has no reflective film 20 under the inclined area K of theinsulating film 21, and the inclined area K of the insulating film 21 isthe transparent display area T. The inclination angle θ of the inclinedplane 21 a of the insulating film 21 is specified to about 50°.

The inclined area K, whether in the transparent display area T or thereflective display area R, is a cause of decreasing the display qualitybecause the retardation is a fractional value. In this exemplaryembodiment, since this area is included in the reflective display areaR, the transparent display does not decrease in quality while thereflective display is slightly inferior in quality. Accordingly, thishas a structure somewhat suitable for a transflective liquid crystaldisplay that attaches importance to transparent display.

Referring to FIG. 12, a seventh exemplary embodiment of the presentinvention is described below.

FIG. 12 is a sectional view showing the structure of a liquid crystaldisplay of this exemplary embodiment. In FIG. 12, components that arecommon to the sectional views of the above exemplary embodiments of FIG.8 and so on are given the same reference numerals and a detaileddescription thereof is omitted.

In the liquid crystal display of this exemplary embodiment, the liquidcrystal layer 50 made of a liquid crystal, which is aligned verticallyin the initial state, is sandwiched between the TFT array substrate 10and the opposed substrate 25 opposed thereto, as shown in FIG. 12. Theopposed substrate 25 has the dye layer 22R constituting areflective-display color filter and the dye layer 22T constituting atransparent-display color filter thereon. The respective dye layers 22Rand 22T of the reflective-display color filter and thetransparent-display color filter have the insulating film 21 in theposition corresponding to the reflective display area R. The commonelectrode 31 is formed on the insulating film 21 and the dye layer 22Tof the transparent-display color filter. Also in this exemplaryembodiment, the insulating film 21 includes the inclined plane 21 a.However, the inclined plane 21 a has no common electrode 31 thereon,serving as a no electrode formed area 31N.

The TFT array substrate 10 has a TFT 110 thereon. The TFT 110 has asemiconductor layer 111 including a source area 111 s, a drain area 111d, and a channel area 111 c, a gate insulating film 112, and a gateelectrode 113. The source area 111 s has a source line 114 (data line)connected thereto. The drain area 111 d has a drain electrode 115connected thereto. To the drain electrode 115, the pixel electrodes 9are connected via a contact hole 117 of an interlayer insulating film116. In this exemplary embodiment, the contact hole 117 does not overlapthe inclined area K of the insulating film 21 of the opposed substrate25 in plan view, but is arranged in the position below the dye layer 22T(planar plane) of the transparent-display color filter.

In this exemplary embodiment, the alignment of the liquid crystalmolecules 50B can be controlled by the shape effect of the insulatingfilm 21 formed on the opposed substrate 25, and further controlled byproviding the no electrode formed area 31N having no common electrode 31on the inclined plane 21 a of the insulating film 21. In addition, thecontact hole 117 is disposed on the TFT array substrate 10 in the areawhich corresponds to a planar plane and does not overlap the inclinedarea K of the insulating film 21 in plan view. Therefore, an electricfield generating in the liquid crystal layer 50 is distorted in thevicinity of the contact hole 117. The distortion of the electric fieldallows much smoother control of the alignment orientation of the liquidcrystal molecules 50B. The broken lines P shown in the liquid crystallayer 50 of FIG. 12 are potential lines. The liquid crystal molecules50B are aligned along the potential lines p, thus being aligned smoothlywithout generating disclination.

[Electronic Device]

Subsequently, a specific example of an electronic device having theliquid crystal display according to the above exemplary embodiments ofthe present invention is described below.

FIG. 14 is a perspective view showing an example of a cellular phone. InFIG. 14, reference numeral 500 denotes a cellular phone body; andreference numeral 501 indicates a display section using theabove-described liquid crystal display.

FIG. 15 is a perspective view showing an example of a portableinformation processing unit, such as a word processor and a personalcomputer, for example. In FIG. 15, reference numeral 600 denotes aninformation processing unit, numeral 601 denotes an input section suchas a keyboard, numeral 603 indicates an information processing unitbody, and numeral 602 indicates a display section using theabove-described liquid crystal display.

FIG. 16 is a perspective view showing an example of a wristwatch typeelectronic device. In FIG. 16, reference numeral 700 denotes a watchbody, and numeral 701 indicates a display section using theabove-described liquid crystal display.

The electronic devices shown in FIGS. 14 to 16 each have a displaysection that uses the liquid crystal display of the above embodiments.Accordingly, electronic devices can be realized which have a light andhigh-contrast liquid crystal display having a wide viewing angleirrespective of use environment.

The technical scope of the present invention is not limited to the aboveexemplary embodiments, and various modifications are possible withoutdeparting from the scope of the invention. For example, while in theabove exemplary embodiments, the present invention is applied to anactive-matrix liquid crystal display using a TFT as a switching element,it is also possible to apply the present invention to an active-matrixliquid crystal display, a passive-matrix liquid crystal display and soon that use a thin-film-diode (TFD) switching element. Specificdescription about the materials, sizes, shapes of various components andso on may be changed as appropriate.

[Advantages]

As specifically described above, according to the present invention, inthe transflective liquid crystal display, the problem of reduction incontrast due to the difference of retardation between the reflective andthe transparent display modes can be addressed or solved, and imperfectdisplay because of the fact that the alignment orientation of the liquidcrystal molecules in the vertical alignment mode cannot be controlledcan be reduced. Consequently, a liquid crystal display of high displayquality can be realized. Also, an alignment dividing structure can berealized depending on the arrangement of the insulating film to achievea wide viewing angle.

1. A liquid crystal display device, comprising: a first substrate havinga first electrode; a second substrate having second electrodes; aplurality of dot areas formed at an overlapping portion of the firstelectrode and the second electrodes, one dot area including atransparent display area for a transparent display and a separatereflective display area for a reflective display; a liquid crystal layersandwiched between the first and second substrates, the liquid crystallayer exhibiting vertical alignment in an initial alignment state; andan insulating film to adjust a thickness of the liquid crystal layer,provided in at least the reflective display area between the liquidcrystal layer and one of the first and second substrates at a position,a thickness of the liquid crystal layer in a center of the one dot areabeing set smaller than a thickness of the liquid crystal layer in aperiphery of the one dot area, the insulating film having an inclinedarea with continuously varying thickness and including an inclinedplane, wherein the inclined plane of the insulating film inclines towardthe transparent display area and is arranged at two opposite side endsof the reflective display area, the inclined plane controlling thealignment orientation of the liquid crystal layer, the transparentdisplay area in the one dot area being adjacent to the transparentdisplay area in an adjacent dot area.
 2. The liquid crystal displaydevice according to claim 1, the transparent display area being disposedto surround a periphery of the reflective display area in the one dotarea, and the insulating film being disposed in an area corresponding tothe reflective display area in the center of the one dot area thethickness of the liquid crystal layer in the center of the one dot areabeing set smaller than in the periphery of the one dot area.
 3. Theliquid crystal display device according to claim 1, the insulating filmbeing selectively disposed in an area corresponding to the reflectivedisplay area in the periphery of the one dot area.
 4. The liquid crystaldisplay device according to claim 1 an electrode to drive the liquidcrystal layer being provided to the substrate having the insulatingfilm, and a no electrode formed area where the electrode is absent beingprovided in at least part of the inclined plane of the insulating film.5. The liquid crystal display device according to claim 4, the electrodein the reflective display area and the electrode in the transparentdisplay area, which are provided on both sides of the no electrodeformed area, being electrically connected through a connecting sectionformed of the same layer as the electrodes.
 6. The liquid crystaldisplay device according to claim 4, the electrode in the reflectivedisplay area and the electrode in the transparent display area, whichare provided on both sides of the no electrode formed area, beingelectrically connected through a connecting section formed of adifferent layer from the electrodes.
 7. The liquid crystal displaydevice according to claim 4, at least one of the first and secondsubstrates being an element substrate having a pixel electrode and aswitching element, and the other of the first and second substratesbeing an opposed substrate having a common electrode and the insulatingfilm, a contact hole to electrically connect the pixel electrode and theswitching element on the one substrate being disposed in the positionnot overlapping the inclined area.
 8. The liquid crystal display deviceaccording to claim 4, an electrode to drive the liquid crystal layer andthe insulating film being provided on one of the first and secondsubstrates, and an electrode to drive the liquid crystal layer beingprovided on the other substrate, the electrode on the other of the firstand second substrates including a window on the outside of the inclinedarea of the insulating film.
 9. The liquid crystal display deviceaccording to claim 1, further including a circularly-polarized-lightradiating device to radiate circularly polarized light into the firstsubstrate and the second substrate.
 10. An electronic device,comprising: the liquid crystal display device according to claim
 1. 11.The liquid crystal display device according to claim 1, furthercomprising: a color filter having a first dye layer for the transparentdisplay and a second dye layer for the reflective display, the colorfilter provided between at least one of the first and second substratesand the insulating film, the first dye layer located in the transparentdisplay area, the second dye layer located in the reflective displayarea, and a color purity of the first dye layer being different from acolor purity of the second dye layer.
 12. The liquid crystal displaydevice according to claim 1, the plurality of structures provided at thetransparent display area arranged at the two opposite sides of thereflective display area in the one dot area.
 13. The liquid crystaldisplay device according to claim 12, the plurality of structures beingwindows of the electrode provided at the other one of the first andsecond substrates.
 14. The liquid crystal display device according toclaim 1, the inclined plane being substantially 5°-50° with respect to asurface of at least one of the first and second substrates.
 15. A liquidcrystal display device, comprising: a first substrate having a firstelectrode; a second substrate having second electrodes; a plurality ofdot areas formed at an overlapping portion of the first electrode andthe second electrodes, one dot area including a transparent display areafor a transparent display and a reflective display area for a reflectivedisplay surrounded with the transparent display area in the one dotarea; a liquid crystal layer sandwiched between the first and secondsubstrates, the liquid crystal layer exhibiting vertical alignment in aninitial alignment state; and an insulating film to adjust a thickness ofthe liquid crystal layer, provided in at least the reflective displayarea between the liquid crystal layer and one of the first and secondsubstrates at a position, such that the liquid crystal layer is thinnerin the reflective display area than in the transparent display area, theinsulating film having an inclined area in the vicinity of the boundarybetween the reflective display area and the transparent display area,the inclined area having an inclined plane so that a thickness of theinsulating film continuously varies.
 16. The liquid crystal displaydevice according to claim 15, the thickness of the liquid crystal layerin a periphery of the one dot area being set smaller than in a center inthe one dot area.
 17. The liquid crystal display device according toclaim 15, an outline of the insulating film in the one dot area being atleast one of an equilateral polygon and a circle.
 18. The liquid crystaldisplay device according to claim 15, further comprising: a color filterhaving a first dye layer for the transparent display and a second dyelayer for the reflective display, the color filter provided between atleast one of the first and second substrates and the insulating film,the first dye layer located in the transparent display area, the seconddye layer located in the reflective display area, and a color purity ofthe first dye layer being different from a color purity of the seconddye layer.
 19. The liquid crystal display device according to claim 15,wherein the liquid crystal layer exhibits vertical alignment in aninitial state.
 20. The liquid crystal display device according to claim15, the insulating film being selectively disposed in an areacorresponding to the reflective display area in the periphery of the onedot area.
 21. The liquid crystal display device according to claim 15,the inclined plane being substantially 5°-50° with respect to a surfaceof at least one of the first and second substrates.